The conventional wisdom is that organic solvents are required to remove most organic residues from the surfaces of equipment used to make organic chemicals, pharmaceuticals and foodstuffs. Organic residues are generally non-polar, or only slightly polar, and thus aqueous solutions do not wet the residues and do not remove them from equipment surfaces. organic solvent cleaning works by solubilizing organic residues; an organic residue is contacted with a quantity of organic solvent until all of the residue has dissolved. Depending on the particular organic residue, one or several organic solvents may be required to thoroughly clean equipment surfaces made of metal, ceramic, glass or polymers. Organic solvents in general use for removing organic residues include petroleum fractions, chlorinated hydrocarbons, toluene, acetone, alcohols, esters and the like.
However, environmental laws and regulations that regulate the use and emissions of organic solvents into the atmosphere are becoming more stringent, and more expensive disposal is required, thus making the use of organic solvents for cleaning more expensive. On the other hand, regulations from the Federal Drug Administration (FDA) and other agencies that monitor the pharmaceutical industry are also requiring a higher level of cleanliness for the manufacture of pharmaceutical products. A very high level of cleanliness for equipment must be ensured for each batch of material produced. Depending on the organic residue present, one or several organic solvents may be required to thoroughly clean the equipment. Organic residues that include ionizable functional groups, such as carboxylic acid groups, hydroxy groups or amine groups, adhere strongly to metal and glass surfaces.
Certain organic materials are water soluble, and thus water-based solutions can be used to remove water soluble organic materials from various surfaces. However, most organic materials are insoluble in water and thus washing in water does not remove these insoluble organics from surfaces.
Thus water-based cleaning solutions that can effectively remove organic residues from the equipment used to make organic chemical products and pharmaceuticals would be highly desirable.